- The banner links (login/logout or My Profile) are determined by
whether or not the user cookie exists (got from backend)
- For the contenders list only (not My Profile), is_owner is determined
by the currently logged in user
- Added logout endpoint
- Cookie query will return a specific user when the cookie doesn't
exist.  For now this is userId = 3, but eventually should be a blank
dumby user with userId = 0.